[clang] [clang][FatLTO][UnifiedLTO] Pass -enable-matrix to the LTO driver (PR #77829)

[Matthew Voss via cfe-commits]

ormris wrote:

Thanks! I'll make sure to include that review in the commit message. Unified LTO is using the ThinLTO pre-link pipeline, regardless of what's passed to the driver. Since the ThinLTO pre-link pipeline doesn't provide this pass, this option should be required when Unified LTO is used. 

https://github.com/llvm/llvm-project/pull/77829